I have young hens that can fly 8 feet up and perch on the roof of their coop. They can't fly as well when they're older and fill out. But generally, with the 6 foot fencing they don't try to fly over it. (yet)
mstricer, I love the feathers on your boy's feet! Someone else mentioned theirs tend to pick off their foot feathers, I think my older gents do that too!